Cam mechanism to clamp magnetic disk against cartridge shell

ABSTRACT

A cartridge for a magnetic disk drive has a clamping mechanism which is actuated as the door to the cartridge is closed when the cartridge is removed from the drive. The door covers the opening through which the cartridge is accessed by read/write heads. When the cartridge is removed from the drive, the mechanism of the present invention clamps the recording disk against the cartridge shell to prevent rattle, which might otherwise damage the recording disk.

RELATED APPLICATION

This application is a continuation-in-part of U.S. application Ser. No.08/477,764 filed Jun. 7, 1995 entitled "Disk Cartridge Anti-RattleMechanism" by Brian Schick.

BACKGROUND OF THE INVENTION

This invention relates to data storage drives and more particularly, toa removable cartridge for magnetic disk drives.

Magnetic disk drives which write and read digital data from flexiblemagnetic disks have been extensively used. "Floppy disk drives" havebeen extensively used for small, so-called microcomputer systems, forword-processing applications and the like. The flexible disk cartridgeincludes a relatively thin, flexible jacket which is inserted into thefloppy disk drive.

Rigid disk drives, such as the IBM 3350, usually have a fixed rigidmagnetic media. The magnetic heads do not contact the magnetic surface,but ride on a thin film of air. Because of this, and other features,these disk drives are capable of extremely precise and high speedoperation. This type of disk drive is commonly referred to as a"Winchester" drive. Rigid disks enclosed in a rigid, removablecartridge, or shell have also been used. U.S. Pat. No.4,864,452--Thompson et al is an example of such a drive.

"Bernoulli" disk drives having performance characteristics similar tothat of Winchester drives, but with removable cartridges, have beendeveloped. A flexible magnetic disk is enclosed in a rigid box which isnormally completely closed. Bauck et al U.S. Pat. No. 4,400,748 andrelated patents to the common assignee show such drives using Bernoullistabilized flexible disks. Jones et al U.S. Pat. No. 4,901,173 andrelated patents to the common assignee, show improvements which relateto so-called "half height" drives.

The cartridges for these drives have a door which closes the cartridgewhen it is removed from the drive. This prevents debris fromcontaminating the magnetic recording medium when the cartridge is not inthe drive. When the cartridge is inserted into the drive, this doorslides to an open position to provide access for the magnetic recordingheads to engage the recording medium.

When the cartridge is removed from the drive, it is often subject torough handling. During handling, physical contact of the disk with theshell may damage the disk, particularly if the disk and cartridge shellare subject to excessive "rattling".

It is an object of the present invention to provide a device whichclamps the disk to the cartridge shell when the cartridge is removedfrom the drive to prevent rattling of the cartridge.

SUMMARY OF THE INVENTION

In accordance with the present invention, a clamping mechanism in a datastorage cartridge is actuated when the cartridge is removed from thedrive. The mechanism restrains the recording medium to prevent rattling.

The clamping mechanism is driven by the motion of the sliding door. Whenthe door is closed (cartridge out of drive) the mechanism expands andrestrains the media from rattling inside the cartridge during handling.When the door is opened (cartridge inserted in the drive) the mechanismcontracts such that it is free of the hub and the media is free torotate.

The mechanism is attached to the sliding door by means of an actuatingwire which provides a spring coupling to allow for mechanism over travelat both ends of the sliding stroke as well as compliance to account forrelative changes in the distance between the mechanism and sliding doorattachment point as the door travels through its stroke. In a preferredembodiment, a member rotatable about the axis of the recording mediumhas an arm connected to the door and attaches the sliding door to themechanism. A wire in an opening in the terminal end of the armtelescopes into and out of the opening as the door travels through itsstroke.

The clamping mechanism includes a rotating cam which rotates in the sameaxis as the media, a translating cam follower, a return spring, and anactuating wire, or arm, which connects the rotating cam to the motion ofthe sliding cartridge door. The mechanism is attached to the cartridgetop shell half. It is situated in the cavity formed inside the mediahub. The mechanism has two states; locked and unlocked. In the lockedstate the translating cam follower applies a force against the media hubeffectively trapping the hub against the cartridge bottom shell. Thisforce is sufficient to prevent the media from rattling against thecartridge shell halves when out of the drive. In the unlocked state thetranslating cam does not contact the hub thus allowing the media to spinfreely.

The foregoing and other objects, features and advantages of theinvention will be better understood from the following more detaileddescription and appended claims.

SHORT DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a top view of the cartridge of the present invention;

FIG. 2 is a front view of the cartridge;

FIG. 3 is an isometric view of the cartridge with the top shell removed;

FIG. 4 is a section on the lines A--A of FIG. 3;

FIG. 5 is a top view of the spindle motor;

FIG. 5A is a section on the line A--A of FIG. 5 showing the cartridge inplace on the motor;

FIG. 6 is broken-away isometric view of the cartridge with the doorclosed;

FIG. 6A is a view similar to FIG. 6 with the door open;

FIG. 7 is a side view of the cam/cam follower assembly with thecartridge door open;

FIG. 8 is a top view of FIG. 7;

FIG. 8A is a section on the line A--A of FIG. 8;

FIG. 9 is a side view of the cam/cam follower assembly with thecartridge door in the open position;

FIG. 10 is a top view of the assembly of FIG. 9;

FIG. 10B is a section on the line B--B of FIG. 10;

FIG. 11 is an isometric view of the cam/cam follower assembly with thecartridge in the open position;

FIG. 11A is an isometric view of the section on the line A--A of FIG. 8;

FIG. 12 is an isometric view of the cam/cam follower assembly with thecartridge door in the open position; and

FIG. 12B is an isometric view of the section on the line B--B in FIG.10;

FIG. 13 is a broken away perspective view of a preferred embodiment ofthe invention with the door in the closed position;

FIG. 14 is a cross-section of the cartridge of FIG. 13;

FIG. 15 is a broken-away perspective view of the cartridge of thepreferred embodiment with the door in the open position;

FIG. 16 is a cross-section of the cartridge of FIG. 15; and

FIG. 17 is a top-plan view of the cartridge with the top shell and disksremoved.

DESCRIPTION OF THE PREFERRED EMBODIMENT

FIGS. 1-4 show a cartridge having two half shells 11 and 12 joinedtogether at 13. The cartridge has a front 14, a back 15 and two sides 16and 17 between substantially flat, planar surfaces 18 and 19. An opening20 in the front of the cartridge provides access by the read/write headsto the recording disks 22, 22A. A flexible door 23 covers the openingwhen the cartridge is removed from the drive.

In accordance with the present invention, a clamping mechanism isactuated as the door 23 is opened and closed. This mechanism includes arotating cam 24 which is rotatable on the same axis as the disks 22,22A. The cam 24 has a surface 25 which extends axially as a function ofthe circumference of the cam. Translating cam follower 26 (FIG. 6) ismoved axially by the surface 25 as the cam 24 rotates. This axialmovement clamps the disk 22 against the bottom half of the shell 11 inthe position shown in FIG. 4.

As shown in FIG. 3, the rotating cam 24 is connected to the door 23 bythe actuating wire 27. Actuating wire 27 provides a spring couplingwhich allows for over-travel at both ends of the stroke of the door 23.Spring 27 also provides for relative changes in the distance between thecam 24 and the point 28 at which the actuating wire 27 is attached tothe door 23. This distance varies as the door travels through itsstroke.

Recording disks 22 and 22A are mounted on a hub 29 (FIGS. 4 and 5A). Aspacer 29A separates disks 22 and 22A. The cam follower 26 applies anaxial force to the hub 29 to clamp the recording disk 22 against thebottom wall 11 of the shell.

A retaining spring 30 is positioned co-axially with the hub 29. Theretaining spring 30 applies torsion to the hub 29 to return it to theposition shown in FIG. 3 after it has been translated by the camfollower 26. A compression spring 31 applies bias to the cam follower 26to return it. A spring 31, which is concentric with, but outside of, thespring 30, provides return force for the cam follower 26 to bring itinto its open position. The springs 30 and 31 are both shown in FIG.11A. The cartridge has a cavity at the center thereof in which theclamping mechanism of the present invention is positioned. A hub cap 32retains the springs in this cavity.

FIGS. 13-17 show a preferred embodiment of the invention in which theconnection between the clamping mechanism and the door is a member 33which is rotatable about the axis of the disks. Rotatable member 33 hasan arm 34 extending radially toward the door 23. The terminal end of arm34 is connected to the door by the wire 35. (FIGS. 16 and 17). Wire 35is disposed in an opening 36 in the arm. The wire telescopes into andout of the opening 36 as the door travels through its stroke. Thisaccommodates the varying radial distance to the door throughout itsstroke.

A protrusion 37 on the arm has a spring 38 which provides the closingforce needed to close the door through the last portion of its travel.The spring 38 has a bent end 39 which travels in the arcuate path 40.The arcuate path has a notch 41 at the closing end thereof. As the bentend 39 travels along arcuate path 40, it drops into the notch 41 at theclosing end of the door stroke. This provides the extra force necessaryto close the door.

Arcuate path 40 is a depression in the face of the cartridge. Thisdepression has a cover 42 so that the spring 38, and its bent end 39travel in a closed path.

Various modifications may be made to the preferred embodiment. Theappended claims are, therefore, intended to cover all such modificationswithin the true spirit and scope of the invention.

What is claimed is:
 1. A cartridge for a drive in which read/write headsread/record data on a recording medium comprising:a shell having afront, a back and two sides between substantially flat, planar surfaces;said recording medium being in said shell; said shell having an openingin the front thereof for access by said read/write heads to saidrecording medium; a door covering said opening when said cartridge isremoved from said drive; a cam rotatable on the same axis as saidrecording medium, said cam having a surface which extends axially as afunction of the circumference of said cam when said cam is rotated assaid door is opened and closed; a translating cam follower which ismoved axially by said cam to clamp said medium against one planarsurface of said shell as said door is closed and to free said medium forrotation as said cam is rotated to open said door; a hub on which saidrecording medium is mounted, said cam follower applying an axial forceto said hub to clamp said medium against a planar wall of said shell; areturn spring positioned co-axially with said hub, said return springapplying bias to said hub to return it after it has been translated bysaid cam follower; said return spring urging said hub away from saidplanar surface as said door is moved to the open position; a cavity atthe center of said hub, said cam, said cam follower and said springbeing in said cavity.
 2. The cartridge recited in claim 1 wherein saidcam is connected to said door to rotate said cam as said door is movedbetween the open and the closed position.
 3. The cartridge recited inclaim 1 wherein said door has a stroke between the open and the closedposition thereof, wherein said cam is connected to said door by anactuating wire providing a spring coupling which allows for over-travelat both ends of said stroke of said door.
 4. The actuator recited inclaim 3 wherein said spring coupling wire is attached to said door at apoint, wherein said door slides in tracks, and wherein said springcoupling provides tolerance for relative changes in the distance betweensaid clamping means and said point at which said spring coupling wire isattached to said door as said door travels through its stroke.
 5. Thecartridge recited in claim 1 wherein said cam is connected to said doorby a member rotatable about the axis of said recording medium.
 6. Thecartridge recited in claim 5 wherein said member has an arm extendingradially toward said door, the terminal end of said arm being connectedto said door.
 7. The cartridge recited in claim 6 and furthercomprising:a wire connecting the terminal end of said arm to said door,said wire being disposed in an opening in the terminal end of said arm,said wire telescoping into and out of said opening as said door opensand closes.
 8. The cartridge recited in claim 1 further comprising:aspring for returning said door to said closed position when saidcartridge is removed from said drive; a protrusion on said memberaxially opposite of said arm; and an arcuate path for said spring, saidspring having a bent end, said bent end traveling in said arcuate pathas said door moves from the open to the closed position.
 9. Thecartridge recited in claim 8 further comprising:a notch at the end ofsaid arcuate path, said bent end of said spring traveling into saidnotch to provide the force to close said door through the last portionof travel of said door to its closed position.
 10. The cartridge recitedin claim 8 further comprising:a cover for said arcuate path, said springtraveling in the covered arcuate path as said door moves between theopen and the closed positions.
 11. A cartridge for a drive in whichread/write heads read/record data on a recording medium comprising:ashell; said recording medium being in said shell; said shell having anopening for access by said read/write heads to said recording medium; adoor covering said opening when said cartridge is removed from saiddrive; and a cam rotatable on the same axis as said recording medium,said cam having a surface which extends axially as a function of thecircumference of said cam, said cam being rotated as said door is openedand closed, a translating cam follower which is moved axially by saidcam to clamp said medium against a planar surface of said shell as saiddoor is closed and to free said medium for rotation as said cam isrotated when said door is opened; said cam being connected to said doorto rotate said cam as said door is moved between the open and the closedpositions; a member rotatable about the axis of said recording medium,said cam being connected to said door by said member, said member havingan arm extending radially toward said door, a terminal end of said armbeing connected to said door; and a wire connecting the terminal end ofsaid arm to said door, said wire being disposed in an opening in theterminal end of said arm, said wire telescoping into and out of saidopening as said door opens and closes.
 12. A cartridge for a drive inwhich read/write heads read/record data on a recording mediumcomprising:a shell; said recording medium being in said shell; saidshell having an opening for access by said read/write heads to saidrecording medium: a door covering said opening when said cartridge isremoved from said drive; clamping means actuated as said door is openedand closed for restraining said medium when said door is closed andfreeing said medium for rotation when said door is opened, said clampingmeans comprising: a cam rotatable on the same axis as said recordingmedium, said cam having a surface which extends axially as a function ofthe circumference of said cam; a translating cam follower which is movedaxially by said cam to clamp said medium against one wall of said shell;a hub on which said recording medium is mounted, said cam followerapplying an axial force to said hub to clamp said medium against saidwall of said shell; and a return spring positioned coaxially with saidhub, said return spring applying bias to said hub to return it after ithas been translated by said cam follower.
 13. The cartridge recited inclaim 12 wherein said cam urges said hub and attached disk against saidwall when said door is in the closed position, said return spring urgingsaid hub away from said wall as said door is moved to the open position.